<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>案例2</title>
		<style type="text/css">
			* {
				margin: 0;
				padding: 0;
			}
			div {
				width: 300px;
				height: 200px;
				margin: 10px auto;
			}
			input{
				width: 60px;
			}
			span{
				color: #228B22;
			}
		</style>
	</head>
	<body>
		<div>
			<input type="text" id="num1">&nbsp;&nbsp;+&nbsp;&nbsp;
			<input type="text" id="num2">&nbsp;&nbsp;=&nbsp;&nbsp;
			<span class="sum">?</span>&nbsp;&nbsp;
			<button type="button" id="btn1">求和</button>
		</div>
	</body>
</html>
<script src="../js/jquery-3.5.1.min.js" type="text/javascript" charset="utf-8"></script>
<script src="./js/test2.js" type="text/javascript" charset="utf-8"></script>